Electric elevator-control system.



ELECTRIC ELVATOR CONTRL'SYSTEM.

APPLICATION FILED SEPT. I. |914'.

Pafented Nov. 13, 1917.

' TSHEETS-jSHEET l.

ELECTRIC ELEVATOR CONTROI SYSTEM.

APPLICATION FILED SEPT. l. 1914.

Patented NQY. 13, '1917.

7 SHEETS-SHEET 2- 8%. Rx @u ek KW. nul m.

N. 0. LINDSTHOM & C. FL E. OLOFSON. ELEcmc ELEVATOR CONTROL SYSTEM. A'PPLICATION FILED SEPT. I. |914.

Patented N ov. 13, 1917.

N.- 0. LINDSTRUM 6L C. F. E. OLOFSON. ELECTRIC ET VATOR CONTROL SYSTEM. APPLlATloN man SEPT. 1. |914.

1 ,24S-,623. Patented Nov. 13, 1917.

' SHEETS-SHEET 4- N. 0. LINDSTROM 8L C. F. E. OLOFSON.

ElECTRIC ELEVATOR CONTROL SYSTEM.

APPLICATION man sEP. 1. 19m.

N. 0. l-.INDSTROM 6L Si F. E. lOLOFSON.

ELECTRIC ELEVATOR CONTRGL SYSTEM.

APPLICATION FILED SEPT. 1. 1914..

rammed N6 13, 1917.

ISHEETS-SHEET 6,-

N.40. LfNDsTR0M @L c. F. E. oLoEsoN. ELECTRIC ELEVATOR CONTROL'SYSTEM. APPL'IC'ATIoN man sEPT. l. 1914.

1,246,623. Patented Nov. 1S, 1917.

f'sHEE'Ts-SHET 7.

l sey, and Jersey City,

JERSEY, ASSIGNORS OLOFSON, OF JERSEY CITY, NEW BROOKLYN, lN EW YORK.

AEIliElCClIRIC ELEVATOR-CONTROL SYSIEIVI.`

Specication oi' Letters Patent.

Patented Nov. is, rei 7.

Application :filed September l, 1914. Serial No. 859,591.

To all w/lwm t may concern.'

Be it known that we, N 4Ins O. LIND'sTRoM and CARL F. OLorsoN, a lcitizen of the United States, and a subject of the King of Sweden, respectively, residing at N utley, in the county of Essex and State of New'J erson and State of NewrJersey, respectively,

have invented certain new and useful Improvements in Electric Elevator-Control Systems, of which the following is a full, clear, and exact description.

The invention relatesto electric elevator control systems and has 'for itsv primary object the provision of a system Which, while the major changes of speed of the motor are controlled from the car, is semiautomaticl in its operation to insure a gradual starting or stopping of the car under varying load conditions.'

nother object of the invention is to provide a system having a dynamic? brake circuit for effecting the stopping of the car, and in which the motor cannot be-run at its higher speeds unless the dynamic brake circuit is intact. Another object of the invention is to provide a series of switches for controlling a line and a dynamic brake circuit for the motor, which switches are controlled in part by the manually controlled switch of the car`and in part by switches automatically controlled by the variations of the load on the motor. Another object of the' invention is to provide a system in which a plurality of switches control the line and dynamic brake circuits and in which the connections for switchesare such that the switches may be only actuated successively and in a predetermincd order, and in which the rapidity of the operation of the switches depends upon the load upon the motor.-

Still another object of the inventionis to provide a system havingja line circuit and a dynamic brake circuit and connections for including a resistance in one or other of these circuits.. Still another object of the invention is to provide a circuit breaker which is controlled by the current flowing through the main line and connections associated with said circuit breaker, so that upon the actuation of the same the system will be inoperative until the actuation of a in the county of Hudactuating saidswitch which is underthe direct control of the operator in the car. Other objects of the invention will be apparent from the v'detailed description and will be particularly pointed out in the appended claims.

In the accompanying drawings, v Figures l and 2 are diagrammatic views of the circuit arrangements of the system, Fig. 2 being a continuation of Fig. l. Fig. 3 is a diagrammatic view of the car switch and connections from the same, which are adapted to be connected tothe circuit arrangements shown in Fig. l.

Fig. i is a diagrammatic view of the motor` and bralre coils, showing the terminals which are adapted to be connected to the main circuit arrangement shown in Figs. l and 2.

Fig. 5 is a simplified diagram ofthe line circuit and the dynamic brake circuit, together with the switches for controlling the same. v A

Fig. '6 is a simpliiied diagram of the circuits for the switches which have been designated '3, 4 and 5.

Fig. 7 is a simplified diagram of the controlling circuits forthe pilot switch for the main switch 3.

` Fig. 8 is a simplified diagram of the controlling' circuits for the pilot Iswitch for switch N o. nel..

Fig. 9 is a simplified diagram of the pilot switch for switch No. 5.

Fig. 10 is a simplified diagram of the controlling circuits for switches 6, 7 8 'and 9.v

Fig. Il is a simplied diagram of the circuit connections to the field and master magnet, and the maximum load and overspced iield ma et showing the same.

Fig. 12 is a simplified diagram of the controlling circuits for the eld and master magnet; and Fig. 13 is a simplified diagram of the controlling.: circuits for the automatic magnet, which controls a part of the dynamic brake circuit. l

In the acompanying drawings Figs. 1 and 2, in which Fig. 2 is a continuation of Fig. l, show a main` arrangement of circuits and switches which are adapted to be placed upon a switchboard in a manner usual in elevator controlling systems of this character, the switchboard being usually placed y switch and is adapted to adjacent the hoisting motor, and Figs. 3 and 4 show the connections from the car switch and the motor, which are adapted to be connected to terminals on the switchboard, as will be hereinafter described.

The various elements which constitute the system are well known, per se, and form no part of the present invention, for which rea,- son--they will not be described-in detail, but in order to clearly bring out the various circuit arrangements which form the features of the invention, the operation of the elevator system will be described and the various circuits for controlling the motor, traced in detail'. Controlling cir/'wit for first Speed of the motor.

Assume vthat the car is at rest and it is desired to operate the motor so that the car will `move downwardly, the load in the car being such that' the motor is taking current from the line,l and also assumethat the circuit breaker and car switch .are in their normal position. Referring now to Fig. 3, a rotary contact or segment 149 is shown, whichv is the controlling segment in a car be actuated by the usual formof handle used for car controllers of the ordinary character used in elevator controlling systems. For the first speed downward the rotary contact 149 is moved to bridge stationary contacts 150 and 151 in the car controller, the result of which is the closing of' a circuit which voperates the electromagnetically controlled down switches 8 and 19 positioned on the switchboard and shown in Fig. 1. rl'fracing this circuit in detail the same starts fromftl e positive side of the line through which the current is supplied to the switchboard, and passes throu h the fuse 1, lead 2, to the contacts 3 of t e main circuit breaker, to wire 4, wire 91, to terminal F2 (shown in Fig. 2) -From here the circuit passes to the'terminal F2 motor shown'in Fig. 4, passing through the shunt field winding 92 to terminal F4 of the motor, and then to the correspondingly marked terminal FAir on the switchboard, shown in Fig. 2, through wire 97, switch arm 140 of the eld and master magnet for switch 10, contact 141, wire 142, resistance 143, wires 144, 145 and 146, fuse 146 wire 147 to the terminal marked L at the top of the switchboard (shown in- Fig. 1). From here the circuitpasses to the wire the endof which is marked L, which leads to the car switch and is shown on Fig. 3 of the drawing, to the pipe L", to the terminal Lc in the junction box, through the cable Ld to terminals Le and Lt in' t e safety switch, to cable Lg, to terminal Lh in the controller box, wire 148 and contact segment 149 to'Y Contact 150. The rotary contact 149 bridges contact 150 with contact 151, the circuit conenergizes the coils 156 and the top of 29 to the negative side of the line. The limit switch -153 which has been referred to in the tracing of this circuit i s of the usual form for limit switches used in elevator systems of this character and is adapted to be actuated by an obstacle in the shaft of the elevator to break the circuit at the termination of the down movement of the car, the use of such limit switches being common,

, The circuit traced also passes through contacts 135 which arecontrolled by the overload magnet of the main circuit breaker, and the function of these contacts will be hereinafter referred to.

The current flowing through this circuit 158 and causes them to attract their armatures 8 and 19 to close the main line circuit through the armature of the motor.

Line circuit for motor mwture;

The actuation of switches 8 and 19 closes a circuit to the motor armature, which starts from the positive side of the line, as before, and passes through fuse 1, lead 2, contacts 3 of the circuit breaker, wire `4, blow-out coil 5, wire 6, contacts 7, armature 8 of one of the down switches, wires 9 and 10, to the point marked R1 on the bank of resistances shown in the middle of Fig. 2, and then through resistance 11, to wire 12, to the terminal marked A2. This terminal is adapted to be connected with the correspondingly marked terminal A2 on the motor, shown in Fig. 4, and the circuit is continued through the armature of the motoigfto the terminal designated A1 on the motor, 'which is connected to the correspondingly marked terminal on Fig. 2 of the drawing. The circuit continues through wire 13, resistances 14, 15 and 16, in series, to the junction point marked LRS, atvthe end of resistances 16, through wires 17 and 18, to the switch-arm 19 of the other down7 switch, contacts 20, wire 21, blow-out coil 22, wire 23 to the terminal marked SB, which is shown in the upper righthand corner of Fig. 2. This terminal is connected to the correspondingly marked terminal on Fig. 4 of the drawings, the circuit continuing through the series coil of the brake magnet to the terminal S2 on the motor, through the series field of the motor to the terminal S1, which terminal is connected to the terminal S1 'shown on Fig. 2.

of the drawings.' immediately below the terminal SB, to Wire 24,1through the low resistance winding 25 ofthe overload magnet of the main circuit breaker, wire 26, contacts 27 of the circuit breaker, lead 28 and fuse 29, to the negative sideof the line.V

Referring now to the simplified diagram shown in Fig. 5, which gives this main line circuit independently of the other circuits of the system, the circuit just traced may be followed, starting from the plus side of the line, passing -through resistance 11, through the armature ofthe motor, resistances 14, 15 and 16 in series, through the brake coil and series el'd to the negative side of the line. It will therefore be seen that the line current through the line circuit at the starting of the motor passes through a series of resistances which will prevent a surge or inrush of current to the motor armature, as is essential in the starting of motors of this character.

Dynamic braise circuit.

In the normal position of the switches there is also closed a dynamic brake circuit which is bridged lacross the motor terminals and is adapted to prevent the motor from speeding up when the load in the car is such that the motor is being driven as a generator by the load, c'. e., will prevent the motor from speeding the same. This circuit, sinceit is bridged across the armature terminals, starts from terminal A2 shown in Fig. 2 of the drawing, and since the switches l and 2 are in their normal or denergized position, will have two parallel branches, one branch passing from A2 to switch arm 30 of 'switch No. 2, contacts 3l, wire 32, resistance 33, wire 34 to a common terminal 34 on a blow-out coil 35, the other .parallel branch passing from A2, as before, through wire l2, resistance 38, wire 39, switch arm 40 of switch No.1, contacts 4l, wire 42, to the lcommon terminal 34 on the blow-out coil 35. The parallel branches unite at this point and pass in common through the blowout coil 35, wires 36 and 37 to terminal designated SR6 at the end of the resistance 43, through this re` sistance to terminal SRE. At this point the circuit again divides, one parallel branch passing through wire 44, contact 45, switch arm 46 of switch No.` 3, wire 48, resistance 49, wire 13, to armature terminal A1 on the -opposite side ofthe armature. The other parallel branch instead of taking thepath through wire 44, continues on through re? sistance 50 to terminal SR4, through wire 51, low resistance coil 52 of switch No.`11,wl1ich has been designated the heavy load magnet or pilot magnet for switch No. 3, and will .hereinafter be described in detail, through wire 53, contacts 54, switch-arm 55 of switch No. 4, to armature terminal A1.

up during the low or rst speed ofY closed after the switch parallel circuit is also closed Referring to the simplified diagram shown in Fig. 5 it will be seen that the circuits just traced comprise two parallel branches 33 and 38, which branches are controlled by switches No. 2 and No. 1, and are con# nected in series circuit again branching at the other end of resistance 43 to form two parallel circuits, including resistances 49 and 50, which are respectively controlled by switches Nos. 3 and 4. This arrangement of the dynamic braking circuit provides a short circuit across the armature. terminals through which the current which is generated by the counter-E. M. F. may pass when the same is acting as a generator, and will therefore serve as anecient brake to insure that the motor will not speed up should the same be driven by the load in the car.

For the second speed the car switch is again actuated to move the rotary contact 149 in a and 171, switch No.1. This circuit parts from the positive side of the line and is identical with the controlling circuit for the `first speed of the motor, to the contact 150 in the car switch. From here the circuit is completed through contact 171, wire 172, limit switch 173, wire 174 to a common terminal 2a for the circuits for both the up and down movements of the car, to the wire 2, cable 2, to terminal 2d in the junction box, pipe lto a terminal marked 2?,.which terminal is adapted to be connected with either of the terminals marked 2f, on the top of the switchboard shown in Fig.` 1, the circuit position to bridge contacts 150 which closes a circuit for actuating continuing through wire 174 wire 175, re-

sistance 176, wires 177 and 178, `wire 180, contacts 296 of switch-arm 19, lwhich are arm 19 has been'actuated, wire 21, blow-out coil 22, wire 23, to the terminal SB, the current continuing i through the series brake coil and series iield shown in Fig. 4, back to the terminal SI on the switchboard, through wire 24, coil 25, wire 26, contacts 27 of the circuit breaker, to the negative side of the line. A from wire 174', which circuit passes down-wire 181 to coil 182, which energizes back to wire 178, which joins the circuit j ust traced. f

When switch No. l is closed the circuit controlled by switch-arm 40 and contacts 4l is opened, while the circuit controlled by switch arm 66 and contacts 65 is closed. The resistance 38, which was previously included in one of the parallel branches of the dynamic brake circuit on the iirst speed of the motor will, in consequence, be disconnected therefrom, and connected in parallel switch No. l, wire 183,

withIthe resistance 11 of the main line circuit. The main line circuit will, therefore, after passing down along the main wire 9, divide at switch No. 1, and part of the current will pass, as before, through wire 10, resistance 11, to amature terminal A2, but another part will pass through contact 65, switch-arm 66 of switch .Na 1, wire 39, resistance 38, wire 12, to the armature A2. From this point the main line circuit remains the same as in the first speed. Since the parallel branch of 'the dynamic brake circuit, which includes resistance 38, is controlled by switch-arm 40, the same will be disconnected from the dynamic brake circuit. The changes in the dynamic and line circuits for the second speed of the Vmotor will be clear from the simplified diagram 'important features of the invention.

shown in Fig. 5.

The particularl arrangement of the dynamic and line circuits described is of particular importance and forms one of the utilizing a dynamic bra-ke circuit having parallel branches it is evident that the current passing through any of the branches which -must necessarily be controlledby a switch, will not be of suiicient strength to heat the contacts of the switch, as might occur if the dynamic resistances were arranged in series and a heavy counter- E. M. F. permitted to pass through a sinvgle switch. This parailel arrangement also insures that the switches for controlling the.

dynamic brake circuit may be opened and closed without destructive arcing. Another important feature is that one of the parallel branches may be disconnected from the dynannc brake circuit and connected in 'parallel with the main line circuit without cut-` ting out the entire dynamic brake circuit which decreases the total amount of resistance required for the system and insures that the current through the line circuit will not be increased until Ythe dynamic brake circuit is weakened, thereby avoiding an unnecessary waste of current.

vthe segment or rotary contact 1 49 bridges contact 184, which closes a circuit for actuating switch No. 2. This control circuit is identical with the control circuit orthe first and second speeds to contact 150, and passes through the rotary contact 149, contact 184, wire 185, contacts 186 ofthe limit switch wireJ 187 to a common terminal 3a for the circuits for both the upA and down movements of the car. The current then passes to the common wire 3?, through cable 3 to the terminal 3d in the ]unction box, to pipe L, to terminal 3 toeither of the terminals 3f, at the top of the switchboard (shown in,

- sistance 196, wires 177 and 178, and the other branch continuing downwardly through wire 191, coil 192, wire 193, which is joined to wire 17 S'. The circuit continues over Wire 180, to switch-arm 19 of the down switch and from this point on is identical with the controlling circuit for the second speed. The actuation of switch No.2 completes a circuit through contact 67 and armature 68, and opens a circuit between contact 31 and switch-arm 30. r1 he breaking of the circuit at contact 31 and switch-arm 30 disconnects the remaining branch of the dynamic brake circuit, which includes the resistance 33 from the armature terminal A". The entire dynamic brake circuit is therefore thrown out of action and the motor is permitted to speed up without .the retarding influence of the brake circuit. The closing of the circuit between the contacts 67 andswitch-arm 68 controls the closing of theswitches Nos. 3, 4,

The closing of switch No. 2 short circuits the resistances 38 and 11, which in the second speed of the motorare in parallel, singe the line circuit which, in' the second speed, passed along wire 9, to contact 65 and switch-arm 66, to the resistances 38, etc., may now pass along wire 9 to contacts 67 and switch-'arm 68, directly to the armature terminal A2.

The closing of switch No. 3 places the resist-- ance 49 of the dynamlc brake circuit in parallel with the resistance in series in the main line circuit. Since switch-arm 69 and switch No. 3 are connected by wire 48 to the point LR on the resistance 49 and contacts 7 0 are connected by means of wire 71 to the point LR3 on resistance 16, the line circuit which has heretofore passed from armature terminal A1, wire 13, through resistances 14, 15 and 16, etc., will therefore have a parallel branch which divides, after passing through wire 13, and continues' through resistance 49, wire 48, switch No. 3, wire 71, to resistance 16, and where it again joins the line circuit heretofore traced, passing through resistance 16 in series. The eiiect of providing these two parallel branches is therefore to increase the strength Eof current which passes through the line circuit. "The closing of switch No. 4 will short circuit resistance 14, since contact 7 3 is connected by means of wire 74 to the point LR* line circuit continuing through the armature to A1 will therefore, instead of passing over wire 13 to resistances 14,15 and 16,

on the resistance 14, and the 14 and 15, included y from armaturel terminal A1 through switch-arm 72 for switch N o. 4, contact 73, wire 74, to point LR, and then through resistances 15 and 16, short-circuiting, however, the resistance 14. Resistance 49 remains in parallel to resistance 15 and the two parallel branches unite at the point LR3 and continue in series through resistance 16 pass , to the negative side of the line, as before.

' wire 80 to the point LR In th No. 5whose contact 7 6 is connected by means of wire 77 to the point LR5, short circuits a part of the resistance 15, and the line circuit continuing from armature terminal A1, will pass directlyto switcharm 75 to switch No. 5, contact 76, wire 77, to the point LR, and then through a part of resistance l5 to the point LRS. The parallel branch through resistance 49 unites with this circuit at this point and 'the two pass in series through resistance 16 to the negative side of the line. The closing of switch No. 6, which is connected situated midway 1n the resistance 16, will sho'rtfcircuit the part of the resistance 16 between the points LR6 and LRS, the parallel branch through resistance 49 uniting with this circuit at the point LRSv and passing in series through the part of the resistance 16 located between LRS and LR",l where the circuit insteadof passing through the remaining portion of the resistance 16, continues through wire 17,

wire 80 tothe switch contact79,switcharm 78 of vswitch line circuit, from which point the line circuit remains the same as before. The closing of switch No. 7 will short circuit the portion of the resistances 15 and 16 which lie between the points LRV and LR". One branch of the line circuit continues'from" armature termi- Y nal A1, to wire 13, throughresistance 49,

len

wire 48 to switch-arm 69 of switch No. 3, contact 70, wire 71, to the point LRS, as before, and then through a portion of the resistance 15 positioned between LRS and LR?, and from there through wire 83 to switch contact 82, switch arm 81 of switch N o. 7, to lead wire 18 of the main line c'rcuit. Another branch passes from armature terminal A1, through switch-arm 75 of switch No. 5, contact 76, wire 77, to the point LRi onresistance 15, and through the part of the resistance' 15 lying between LRs and LR7, to wire 83 where it unites with the arallel branch through resistance 49. A third parallel circuit will also be closed from A1, through wire 13, resistance 49, wire 48,V larmature 69 of switch No. 3, wire 71, to the point LR3 on resistance 16, through the part of resistance 16 between LR3 and LR", wire 80, contact79, switch-arm 78 of switch No. 6, to the'lead 18 and the negative side of the line. The closing of switch No. 8 short circuits resistances 14, 15, 49..and 16 as an ene same mannerythe closing of switch by means ofA N o. 6, to the main wire 18 vof the- `resistance 240, wire tirety and the main line circuit then pass rom armature terminal A1 to switch-arm 75 of switchNo. 5, contact 76, wire 88, coil 87 of the maximum load and over speed field magnet which has been designated switch N o. 14, and will be hereinafter referred to, wire 86, contacts 85, switch-'arm 84 of switch No. 8, wire 18,- and then as before, to the negative side of the line. The closing of switch N o. 9short circuits ing of the motor and brake, or in other Words, short circuits the compounding eifect of the motor, which will weaken the field of the motor and hence increase the speed thereof, as the line circuit which heretofore has flowed along wire 23 to the terminal marked SB- on the switchboard and then through the series brake and series field, will, when the switch-arm 89 is actuated, pass directly to the point S1 where the line circuit will continue as before, through wire 24. The effect of closing these switches succes`- sively in the order g1ven, is to gradually cut down the resistance ofthe main line circuit so that the current which is supplied to the armature of the motor will be gradually increased and the motor permitted to have a gradual increase of speed without any liability of an inrush of cur-rent through the armature. In other words, one-of the functions of switches 3 to 9 inclusive, is t gradually cut down the starting resistance in the main line circuit, whichis'essential in elevator systems of this character. Part of these switches are also used to control the dynamic brake circuit, as will be hereinafter described. p Y

Operating circuits for switches 3, 4 and 5.

Referring to Figs. 1 and 2 of the drawing.d it will be seen that switches 3, 4 and 5 are controlled by coils 242, 251 and 257 respectively, so that upon energization of these coils the switches will be closed. The cir,- cuits for these coils are in turn controlled by auxiliary switches which have been designated switches 11, 12 and 13 respectively, switch 11 controlling the circuit for Switch No. 3, switch No. 12 for switch No. 4, and switch No. 13 for switch N o. 5. On the closing of the auxiliary switch No. 11 a circuit will be closed from the positive side of the line, through fuse 1, lead 2, contacts 3 of the i circuit breaker, wire 4, wire 91, wire 235 to switch-arm 236 vof switch No. 11, to contact 237, wire 238, at which point the circuit divides, one branch passing through wire 239,

branch passing 242 of switch No. 3, wire 243, to wire 24, where it unites with its parallel branch and the common circuit passes through the low resistance coil 25 of the circuit breaker, wire .26,l contacts 27 of the circuit breaker, lead 28, fuse 29, to the negative side of the line.

241, to wire 24, the other down along wire 238 to coil negative side of the line, as in the .previous circuit traced, while the other bran 1 passes down along wire 247, wire 250, coil 251, -wire 252, wire 243, to the main wire 24, where it passes to the negative side of the line, as before. The circuit for switch No. 5 is in the same manner controlled from contact 246 of switch No.12, that is, pilot magnet for switch No. 4, where the circuit continues from these contacts over wire 253 to arm 254 of switch No. '13, that is, pilot magnet for switch N 0. 5, contact 255, wire 256, where 'the circuit divides, one branch .passing `through wire 257,

resistance 258', wire 241, to the main line, wire 24 on the negative side of the line, while the other branch continues over wire 256, coil 257, of switch No. 5, wire.258, wire 243, which connects to the main wire 24 on the negative side of the line, as in the previous circuits.

Referring now to the simplified diagram shown in Fig. 6, and tracing these circuits on the same, 1t will be seen that the terminal wires 91 and 241 and 243 of the circuits just traced, are directly connected to the main line wires 4 and 24 between the sources of supply and the up and down switches, for which reason the direction of current, through these circuits will remain the same on both the up and down movement of the car. It will be clearly seen from this diagram, that the coil 251 of switch No. 4, cannot be energized until switch No. 3 has been actuated, and in the same manner coil 257 of the switch No. 5, cannot be actuated until the pilot magnet for switch No. 4 has been.

closed, which will insure that these switches .will close successively andv in the order named, to gradually cut out the line resistance, as has been described. The operation of these switches, when the car is slowing down, will be hereinafter set out. It will also be apparent from this diagram that each of the coils 242, 251 and 257 have connected in parallel with them, resistances 240, 249 and 258 respectively. These resistances have two functions; rst, they 'serve as retarding coils to prevent the switches, after the controlling circuits have been broken at the auxiliary switches, from returning to their normal position too rapidly, since they retard the flow of inductive current through the circuits, and hence will retain the coils energized for a longer time than if they were not used. The resistances also serve same purpose,

to choke the inductive eiiect and therefore prevent destructive arcing at the pilot switches when the circuits are broken at these points.

Throughout the description which will be hereinafter given, the resistances whichare arranged in parallel with a coil are for the and their function will not again be referredl to.

Controlling circuits for switch N o. 11.

Switch No. 11, which has been designated the heavy load magnet or pilot magnet for switch No. 3, has its switch -arm 236 controlled by two coils which have been designated 52 and 214, respectively. As has been heretofore described, the low resistance winding coil 52 is connected in series with one of the parallel branches of the dynamic brake circuit, or that branch of the dynamic brake circuit which includes resistance 50. The circuit referred to after passing through resistance 50, continues on through wire 51, to coil 52 and thence to wire 53, to switch No. 4, as has been described.

The high resistance coil 214 and low resistance coil 52 are differentially wound so that when energized they set up an opposing flux. The high resistance winding 214 1s connected in circuit with the main line circuit by a branch in parallel to the motor armature which passes from the main line circuit at armature terminal A2, along wire 12, wire 217, resistance 216, wire 215, high resistance winding 214 of the coil, wire 213, wire 200, wire 18, to the negative side of the line.

Referring now to the simplified diagram shown in Fig. 7 in which these controlling circuits are shown apart from the remaining circuits of the system, it will bevclear that the coil 52, being connected in series with the dynamic brake circuit, `depends upon the counter-E. M. F. developed by the motor, while the high resistance winding 214`depends upon the current supplied to the main line. As this switch is not controlled by the car controller and does not depend directly upon the actuation of any of the other switches of the system, but is entirely automatic, its operation will be clearly described.

current which passes through this winding 214 will not be suiicient to energize the same. This is true whether the motor has started to turn or not. Upon the second speed of the motor, switch 1 being actuated to throw resistances Hand each other,

E. M. F. 'The effect of the closing of switch` No. 3 at this time will therefore be to inf crease the current supplied to the main line, so that the motor armature begins to rotate and take care of the load. It is-for this reason that this switch has been designated theheavy load magnet, as it will always insure that even under the heaviest loads the shown, it will motor will start to turn when the second speed has been reached. However, if upon the actuation of switch No. 2 from the car control, the motor armature has begun to rotate, the counter-E. hl. F. developed by the motor will send a current through the dynamic brake circuit which includes the low resistance coil 52. As this coil is wound to oppose the coil 214, switch No. 11 will not be actuated if the motor has begun to rotate at the required speed for w 'ch the machine is designed to run, at thisspeed, and switch' `No. -11 will therefore not be thrown into action until the operator 'in the car has actuated .his car switch for thethird speed.

On the third speedl the dynamic brake circuit is broken by switch No. 2, as has been described, and since no current can flow through the low resistance coil 52, the switch No. 11 will always be actuated by the energization of coil 214, when this point has been reached. From the simplified diagram also be clear that the coil 214, since it is bridged across the motor terminals, 1s parallel to the dynamic brake circuit and will also receive current when the motor is turning and developing a counter E. M. F. The importance of this feature will be further described in the slowing-down of the motor.

Controlling circuit for switch No. 12.

lSwitch No. 12, or pilot magnet for Switch No. 4, is controlled by means of two high resistance windings 219 and 233 which are cumulatively wound and aid each other in attracting the switch arm `245 to close the circuit at contacts 246.

Referring to Figs. 1, 2 and 8, the latter showing a simplified diagram of the control circuits for the switch, it will be Seen that the circuit for the winding 219 is connected to the main line and isbridged across the armature terminals by connecting it to a part of the dynamic brake circuit when contacts 31 of switch No. 2 are open. This circuit starts from wire 9 and armature terminal A2 and passes to wire 12, Wire 217 and wire 218, coil 219, wire 220, resis ance 221, wire 222, contacts 31 which are controlled by switch lilo. 2, ywire 32,. resistance across the motor terminals, depends upon the counter E. M. F. developed by the motor, since the higher the E. M. F. of the motor the greater is the amount of current which will pass through the parallel branch. The winding 233 is connected in parallel to the motor armature and serves, when switch No. 5 is closed, to aid the coil 219 in attracting the armature. When the motor is slowing down and switch No. 5 still remains in its attracted position, this circuit is in parallel with a part of themain line and dynamic circuit through portions of resistances 56 and 14, the parallel branch passing through a portion of the resistance 56to the point SRS, Wire 58, to contacts 59 of switch No.

5, wire 234, coil 233, wire 232, to a point on the resistance 14, where it again joins the main linecircuit and passes through to the negative side of the line. Als/soon as switch arm 60 of switch No; 5 makes contact with 59, this circuit is short circuited by the short lcircuiting of the part of the resistance 56 which is in parallel to it.

0mm-@zang @acca for maar. No. za

Y resistance coil 226 which is energized from the main line when current is passing through the same by a circuit starting from wire No. 9 and passing to contact 65 of switch'No. 1, arm 66 of the switch, wire 39, wire 223, resistance 224, wire 225, winding 226 of the coil, wire 227 to the point P5 on resistance 33, through resistance 33, wire 34, blow out coil 35, wires 36 and 37, resistances 43 and 59 to the point SR5 on resistance 56, wire 58, contacts 59, switch-arm 60 of switch No. 5, and through resistances 15 to 16 to negative side of the line, resistance 14 being short circuited since No. 5 is not actuated until after switch No. 4 has been closedD The current which passes through this circuit depends upon the counter E. M. F. developed by the motor, since the wire 12, switch-arm 66, contact 65 is connected to wire 9, which therefore bridges the coil across the armature terminals and as the counter E. M. F'. cf the motor increases, since the same will oppose the line current passingthrough the same and a greater amount ot line current will therefore pass through the parallel circuit which includes the coil 226. lf no current is passing through the main line and switches No- 2 and 1 have resumed their normal positions,

the coil 226 will still be energized by the counter E. M. F. developed by the motor under certainconditions which will be hereinafter brought. out more fully in the description of the operation' of the system when the motor is slowing down, the coil being bridged across the motor terminals by means ofwire 12-switch-arm 30, contacts 31, part of resistance 33 to the point P5, wire 227, coil 226, wire 225, resistance 224, wire 223, switch-arm 40 of switch No. 1, contacts 41, resistance 43 and then through resistances 50 and 56 back to the other armature A1.

Controlling circuits fofl switches 6', 7, 8 and .9.

Referring to Figs. 1 and 2 and Fig. 10 of the drawin s, the controlling circuits for switches 6, 7, 8 and 9 are shown, which are closed in the order named to successively short circuit sections of the resistance of the main line, as has been described. The circuit for the coil 262 of switch No. 6 starts from the armature terminal A2 and continues over wire 260 and wire 261 to coil 262 of switch No. 6, wire 263 to the point marked 6a on the resistance 264, wire 265, which is joined to wire 222, and the remaining portion of this circuit continues through ccntact 31 of switch No. 2, resistance33, wire 34, coil 35, wires 36 and 37, resistances43, 50 and 56, to wire 57 and thence to armature terminal A1, the circuit passing through the entire resistance 56 in this instance, since when switch No. 6 sactuated switch No. 5 is in its closed-position so that the connection from wire 58 to contacts 59 and switch arm 60 of switch No. 5, to armature terminal A1, is opened. It will also be seen that this circuit is closed only after switch No. 2 has been actuated to disengage the contact 31 from switch arm 30 of switch No. 2, as

`otherwise the circuit would be short circuited by this switch and the circuit would pass directly from armature terminal A2 to resistance 33, as has been before described. In the same manner the circuit for coil 267 of switchl No. 7 starts from armature terminal A2 and passes along wire 260, to wire 266, coil 267, wire 268 to the 'point marked 7 on the resistance 264, to wires 265 and 222,

to contacts 31, where the circuit continues to the other armature terminal A1 over the same path as did the circuit for the coil 262 of switch No.' 6. Current for the coil 270 of switch No. 8 is also supplied from wire 260 from which the branch wire 269 connects the same with coil 270, the circuit continuing over wire 271 to a point marked 81 on the resistance 264, and through this resistance to wires 265 and 222 to the other Side of the armature as in the preceding circuits. The circuit for coil 272 of switch No. 9 branches from wire 260, passing through wire 272', coil 272, wire 273, high resistance coil 274 magnet which will be hereinafter described in greater detail, to the point marked 91 on the resistance 264 and through this resistance to contacts 31 and the other armature terminal A1. each of these circuits has an additional resistance included in the same so that they will, when energized by the counter' E. M. F. developed by the motor, close in the ,order named. The switch 8, however, is connected to pass through a greater portion of the resistance 264 than 1s the circuit of the coil 272 of switch No. 9, since this latter circuit also includes in it the high resistance coil 274 of the maximum load and over speed i'eld magnet, which makes this necessary in order that the resistance of the various circuits will be graduated so that the switches will successively close.

It may here be stated that speed.

When switch No. 2 has been actuated upon the throwing of the car switch to the third speed position rst switch No. 2 throws out the dynamic brake resistance and also increases the current through the line, since resistances 11 and 38 are short circuited. The automatic switch No. 3 which is ncontrolled by auxiliary switch No. 11, is then adapted to be closed only after switch No. 2 has been actuated, if the motor is taking current from the line. If, however, upon throwin the car switch to the second speed the loa is so heavy that the armature has not started to turn, switch No. 3 will be actuated before switch No. 2, to start the motor rotating. After the armature has started to rotate the remaining switches 4 and 5 will be actuated as the counter-E. M. F. developed by the motor will be increased, but

these switches can only close after switch.

Connections for controlling shunt field by master magnet and masmmn load and over speed magnet.

Heretofore, the only circuit described which has passed through the shunt field of themotor has been thel controlling circuit .which passes through the car switch and through the low resistance field coil 92. The shunt field of the motor, as shown in Fig. 4, of the drawings, comprises two low resistance windings 92 and 98, and high resistance windings 100 and 102, which are energized from a circuit, starting from fuse 1, through iso' lead 2, contacts 3 of the circuit breaker, wire 4, wire 91 to terminal F2, shown in the upper portion of Fig. 2, which is adapted to be connected to the correspondingly marked terminal on Fig. 4, through lowresistance winding 92, high resistance winding 100, wire 101, high resistance winding 102,`low resistance winding 98, to terminal lFl on the motor and switchboard, to wire 99, to the point marked S1 on Fig. 2, wire 24, coil 25, wire 26, contacts 27 -of the circuit breaker, lead 28 fuse 29 to the negative side of the line. This circuit has been shown on the simplified diagram shown in Fig. 11, from which it will be seen that the shunt winding of the motor as it should be, is connected across the main line circuit, which circuit which the switch arm is adapted to` engage,

will be supplied with current as long as there is current flowing in the main line. The high resistance windings 100 and 102 are adapted to be short circuited during the slow speeds of the motor by the field and -master ma et, the controlling circuits of which will be hereinafter described, whereby the current which the motor may develop, but decreasing the speed fof the same.` The iield and master magnet which has been designated switch No. 10, is provided with a switch-arm 96 which is connected by the wire 97 to terminal F 4 on the switchboard, and which is adapted to be connected with .the correspondingly marked terminal on the motor. Contact 95 with is connected by means of wires 94 and 98 to terminal F3 on the motor and switchboard,

so that when this switch is closed wires 97, 94 and 93, together with switch-arm 96 and contacts 95, form a short circuit around the high resistance windings, which is the condition of th'e shunt field during all speeds of the motor except the highest as w11l` be hereinafter described. To strengthen the shunt field the maximum' load .and v over speed field magnet is utilized so that'on a maximum load where an increase offpower is desired the ield may be strengthened,A or,

1f the motor is speeding 'the strengthening of the eld will produce a corresponding decrease in speed. This switch has been designated No. 14,' 'and its switch-arm 105 is connected by means of wire 106 and resistance 107, to the -motor terminal F4, while the corresponding contacts 104 are connected to the common wire 93, by wire 103 which leads to motor terminal F3. 1t will therefore. be seen that when this switch is closed, the resistance 107 is placed in parallel with the high resistance shunt-field winding and in series with the low resistance shunt winding so that there *will` be a material increase of current passing through the low resistancel shunt fieldl winding, which which passes through- Y the shunt eld will be materially increased, increasing the power positive line as before,

through switch-arm30 field l strengthens thesame and increases thepower Yof the motor and also decreases its speed.

windings which are cumulatively A the main line circuit, starting from wire 9,

and passing through wire 205, resistance 204, wires 210 and 212, coil 211 of the held magnet, wire 206wire 197, resistance 198, wires I199 and 200, to wire 18, and then .foliowing the main line circuitto the negative side of the line. When the car switch is moved to its first, second or third position, since the circuit just traced is in parallel to the main line, there will necearily' bea flow of current to the same which will energize coil 211 toattract the armature of the field and master magnet to its closedl position so that the high resistance shunt field windings 100 and 102 will be short circuited and the field ofthe motor thereby strengthened to supply the` additional power to run the motor up to speed;V The circuit for the other winding 230 is also in parallel with the main line and dynamic c1rcuits\and serves as an aid --to attract the armature of the switch 10 when either the moto is slowing down, or if the controller hand e should be moved to its fourth speed position so rapidly that the winding 211 has not an opportunity-to 'attract the armature, as will be hereinafter referred to. This circuit starts from the and passes through wire 9, wireV 10, resistance 11, wire 12,

of switch No. 2, contacts 31, wire 32, through resistan'ce33 to the p'oint marked MM on the same, wire 231, coil 230, wire 227 resistance 228, wiresl 199 and 200 tothe negative side of the line.

As will be clear from Fig. 12 it will be seen .that this circuit receives current as long as the resistances 14, 15 and 16 are in series with the main line circuit, but when these resistances'are cut out of circuit by the actuation of switches 3, 4, 5, etc., thls circuit will also be short circuited and the magnet 230 denergized. ,c

As will be hereinafter explained, coil 211 is denergized mainly from the car switch, and supposing this should` occur beforexthe magnets for the thirdspeed position have` net will, under these circumstances, attract the armature of the field and master magnet until the line resistances 14, 15 and 16 are cut out of circuit, after which time it -is the car is slowing down, will be hereinafter described in conjunction 'with this feature of the system.

Controllg circuits for the fourth speed.

If the car switch is moved to the fourth onhigh speed position for downward movement of the car contact 149 will bridge contacts 150 and 194 and the circuit will continue from contact 150 over the circuits previously traced, to contact 194, wire 195 to the terminal Dt, cable 3c to terminal D* in the junction box, through the pipe L", to terminal D4 at the top of thepipe which is adapted to be connected with the terminal D4 atthe top ofthe switchboard, shown in Fig. 1. rThe circuit continues down wire 196, Wire 197, resistance 198, wire 199, wire 200,

`to 18, on the negative side of the' line, since for the downward movement of the car the down switches 8 and 19 are closed, making the main wire' 9 the positive side of the line and thewire 18 the negative side of the line. The circuit which passes from terminal D4 to wire196, wire 197, etc., to the negative side of the line therefore opposes the current passing through the coil 211, as will be clear from Fig. 12, and this winding will thereforebec me denergized to permit its armature to resume its normal position, breaking the circuit around the high resistance shunt iiel'd windings, and therefore weakening the field to give the desired in- Y crease of speed..

The action of the fourth speed is vthe same for the up movement of the car, which will now be described in detail.

4trolling circuit' for the down movement to wire148, which is connected to contacts 150 and 160 in parallel. The circuit then continues to contact 149, through contact 162, wire 163, limit switches 164 for the up movement of the car, which are similar tothe limit switches for the down movement, over the wire 164', cable 2c, ter` minal UD in the junctionbox, pipe Lb to the terminal U", which is adapted to becon- 1,24e,ees Y load magnet of the circuit-breaker, wire 136,

fuse 29, to the negative side of the line, this circuit being common to thel circuit for the down movement of the car, over wires 132 'and from there to the negative side of the line. The actuation of the switches 1.10

and '111 closes a main line circuit which starts-from the positive source of supply,

Athrough the fuse -1, to lead 2, contacts 3 of the main circuit-breaker, lead 4, blow-out coil 5, wire 6, through contacts 109 of the up switch, through the switch-arm 110, wire 18, to wire 17, resistances 16, 15 and 14, wire 13, to armature terminal Af, and then through the armature of the motor in the opposite direction to the current which passes through the same on the down movement of the car, to 'armature terminal A2, wire 12, resistance 11, wire 10, wire 9, to switch-arm 111 of the up switch, contacts 112, wire 113, wire 21, blow-out' coil 22, wire 23,v to the terminal marked SB which is connected to the series brake coil, as in the circuit for the down movement of the car, to terminal S2 on the motor (see Fig. 4) through the series eld in the same direction as in the down movement of the car, to terminal S1, which is connected to the correspondingly marked terminal S1 on Fig. 2, the circuit continuing over wire 24, coil 25 of the overload magnet of the lmain circuitbreaker, wire 26, contact 27 of the circuitbreaker, lead 28, fuse 29, to the negative side of the line. It will be seen from the tracing of this circuit that the current which passes through the armature of the motor has been reversed in direction, while the current which passes through the series brake coils and series ield windings is unchanged in direction, which'will reverse the direction of rotation of the motor.

lEhe direction through the shunt field of thev motor remains the same as for the down movement of the car, since, as will4 be clear from Fig. 11, wire 91 which connectsthe 'circuit for the shunt eld windings tothe system, is connected to the lead wire 4 `which remains positive for both the while the wire 99 which connects the other end of the circuit to the system is connected to wire 24, which remains negative for the main circuits for both the up and down movements of the car, so that the direction of current throughthe shunt field remains unchanged.

"up and down movements of thecar,

movement of the car, and is the same as the movement or the car,

circuit which hasbeen traced ior the ener-- gization of coil 182, which will then be energized'to close switch No. l, as has been previously described. For the thirdspeed up movement contacts 160 and 204 are bridged and the current iiows from contact 204 to wire 205, limit switch 206, to the common terminal 3a, from which point the controlling circuit is similar to that traced for the third Speed down movement of the car, and inthe same'way switch No. 2 will be actuated.

4As will be clear from the simplied diagram shown in Fig. 6, the circuits for the magnets of switches 3, 4 and. 5,*are connected tol the main lead 4 by means of wire 91 and are connected at their other ends to the negative wire 24 of the main line by means of through Wires 4 and 24 direction for the up ments of the-car, ofcoils 3, 4 and 5 the' up and down movements. The cirdoes not changeV in anddown moveso that the energization cuits for. the auxiliary switches 11,' 12 and 13, that 1s, pilot magnets for switches Nos. 3, 4 and 5, will be energized in exactly the same manner on the up movement of the car since, as will be clear from the simplified diagram shown in Figs. 7, 8 and 9, the direction of current through each of the coils will be reversed.

Referring now to the fourth speed up in which contact 207 is electrically connected to contact 160 through rotary contact 1.49, the current will flow through the controlling circuit as before, to contact 207 and lthen through wire 208 to terminal U4 (see F ig. 3) through cable 2, to terminal lU4 in the junction boX, then through the pipe Lb to terminal U4 which is adapted to be connected to the terminal U4 at the top of Fig. 1, the circuit continuing through wires 209 and 210, resistance 204, wire 205 to wire 9. Referring .to the simplieddiagram lshown in Fig. 12,

it will be seen that the positive side of the line is connected through' wires 209 and 210,

through resistance 204, to the wire 9 which,y

a common wire 243. 'The current A will be identical for bothl vthe contro the second and switch same manner,

Rc1/aiding coil for switch No.

In order to prevent the actuation of switch No. 2 until switch No. 1 has been actuated, which might' occur if the car switch were rapidly worked toits third or fourth speed positions, retarding coil 291 is provided. This coil vreceives its current from the main line branching from the wire 9 and passing through the wire 292, to coil 291, wire 290, which joins with wire 39, being in parallel therefore, with the line resistance 11. This circuit, however, is shortcircuited upon the closing of switch No.- 1, for when this switch is actuated the current will take the .path through the relatively1 low resistance 38 instead of through the high resistance coil 291, so that the retarding coil only holds .the armature of switch o. 2 in its normal position. as long as switch N o.

Action olf switches upc/n the breaking of Zing circuits-lf the controlling circuit for the fourth speed, either up or down4 motion, isbroken inthe car by the operator .moving rotary contact 149 "either out of contact with contacts 194 or 207, the circuits which oppose the current passing through the winding 211A of switch No. 10, that is, thek ield andmaster magnet, will be broken so that coil 211 again is energized fromthe main line to shor -circuit the high resistance shunt field windings to thereby increase the strength of the field and to cut down' the speed of the motor. As'will be clear from Fig. 3, no limit switch is provided for the fourth .speed of the car, but for the yfirst, second and third speeds of the car, upon upward movement of the same, three limit switches are provided, namely, switches 164, 203 and 206, which are adapted to be broken by a device in the shaft of the elevator, asis the common practice, the third speed of the motor, switch 203, 164 the first, which switches are adapted to be broken -as the car completes/its vupv movement. In the limit switches 153, 173 and 186 control the third, second and flrst speeds of the motor upon down movement of the same and are adapted to be actuated to break the control circuits as the car completes its movement in a downward direction.

If the controlling circuit for' the third 'speed is broken either by means of the' car and to thereby 1 remains in its normal position.

switch, which is accomplished by moving rotary. contact 149 either out of contact with contacts 205 or 194, or is broken by means of the limit switches 153 or 206, the coil 192 of switch No. 2 is denergized `and this switch resumes its normal position, closing contact between the switch arm 30 and contacts 31 and opening circuit between switcharm 68 and contact 67. As will be clear from the simplified diagram shown in Fig. 5, the closing of a circuit between switcharm and contacts 31 will' again complete the' dynamic brake circuit current passing from armature terminal A2, switch-arm 30, contacts 31, resistances 33, 43, 50 and 56, wire 57, to armature terminal A1, which dynamic brake circuit is of relatively high resistance but will gradually slow down the motor if the counter-E. M. F. developed by the motor is high. As will be clear from the simplified diagram shown in Fig. 10, each of the coils which control switches 6 to 9 inclusive, pass to a common wire 260 and then through the coil of these switches in parallel, to a portion of theresistance 264,

` to resistance 264, to a cominon wire 265, and

thence to contacts 31, to resistances 33, 43, 50 and 56 to armature terminal A1. Upon the closing of contacts 31v and switch-arm 30, the circuit instead of passing over wire 260 to each of the coils, will therefore pass directly to switch-arm 30 and contacts 31, and thence to the resistances, thereby shortcircuiting each of the coils of these switches.

Upon the closing of switch-arm 30 and contacts 31 each of these coils will therefore be denergized almost simultaneously and the switches will resume their normal positions. The opening of switch No. 9 will break 'the' short circuit around the series brake coil and series eld winding, thus introducing more resistance in the line circuit and at the saine time increasing the strength of the field to thereby decrease the speef.

e opening of switches 6, 7 and 8 will breakthe motor and increase its power.

the short circuit around portions of the resistances 15 and 16 to thereby introduce more resistance in the main line, which will. result in a gradual slowing down of the motor.

1f the circuit for the third speed should be broken by means of the limit switches rather than by the actuation of the car switch from the fourth to the third speed, it is evident that coil 211 which normally actuates the armature of the eld and master magnet, will remain denergized, since the car switch still remains in a position to oppose any current passing through the same, and it is therefore necessary to energize this switch-by means of 'the coil230 in order to short-circuit the high resistance field windings of lthe motor. This is accomplished, since the other winding 230 which actuates switch-arm 96 of the eld and master magnet is also in parallel to the line circuit, through a part of the resistance 33 and resistances 14, 15 and 16 respectively. After switch No. 2 has closed and switches 6, 7 and 8 have been opened to include a part of the resistances 14, 15 and 16 in the main line circuit, current will pass through the Winding 230 starting from a wire 9, lthrough resistance 11, wire 12, switch-arm 30, contacts 31, wire 32, resistance 33 to the point MM on the same, wire 231, wire 30, wire 227, resistance 228 wires 199 and 200, to wire 18, which coil will then be energized to attract the armature and short-circuit the high resistance shunt field windings, as described, which circuit will remain energized as long as current is supplied to the motor. This coil will also be energized if no current is being supplied to the main line, since the current 230 is bridged across the motorfterminalsand in parallel to the dynamic brake circuit as will be vclear from Fig. 12, which will hold the coil energized as long as the motor is turning and developing a counter E. M. F. Since the lower contacts of the field and master magnet control the contacts 141 in the main controlling circuits which.

pass to the car switch, the fact that the field and master magnet remains in its attracted position until the motor is stopped, is important since it prevents the motor from Aagain being started until it has come to a full stop. For the third speed of the motor,

in slowing down, switch No. 2 and switches I 9, 8, 7 and 6. are alone actuated, switches 3, 4 and 5 remaining closed, as will now be de scribed.

Switch -Nd 3 .remains energized since the coil 214 is in parallel with a part ofthe main line circuit which includes resistances 14, 15 and 16, and will therefore 'receive sufficient current to maintain it energized. Even if there is no current flowing through the main line, the coil 214 will still remain energized since it is bridged across the armature terminals through the line resist- -is bridged across the dynamic circuit in parallel with a portion of resistances 56 and line resistance 14. The coil 226 of switch No. 13, that is, pilot magnet for switch No. 5, also receives current through a dynamic brake circuit assing from armature A, wire 12, throng resistance 38, wires 39 and mature terminal A1.

223, resistance 224, wire 225, coil 226, wire 227, to resistance .33, then through resistances 43, 50 and 56 to the other side of the armature, that is A1.

Should the controlling circuits for the second speed be broken either by means of the car switch or by the limit switches, the-coil 182 of magnet for switch No. 1, becomes denergized and the switch-arms 66 and 40 resume their normal position to close contact between switch-arm 40 and contacts 41 to open it between contact 65 and switcharm 66.

Referring v to the simplified diagram shown in Fig. v5, the closing of contacts 41 will disconnect the resistancel 38 which, when switch No. 1 is open, is in parallel with the line resistance 11 and again connect it into the dynamic brake circuit and -in parallel with resistance 33. Thedynamic brake circuit is now strengthened and will give a stronger short circuit effect across the motor armatures where a rapid slowing down of the motor is required, as where the same is being driven as a generator by the load. Switches Nos. 5, 4 and 3 will now resume their normal positions in the order'given.

Referring first to the operation of switch No. f-From the simplified diagram shown in Fig.l 9 it is clear that the high resistance coil 226, which controls the pilot magnet for switch No. 5, is bridged across t e motor terminals, the circuit passing from terminal A2, through wire 12, to resistance 38,-

wire 39, wire 223, resistance 224, wire 225, coil 226, wire 227, to the point I"s onresistance 33,Y and through the dynamic resistances 33, 43, 50 and 56 to the other ar- Upon the closing of switch No. 2 the `circuit through the -coil 226 will still remain energized, although a portion of the dynamic brake circuit current will now pass directly from wire 12 to switch arm 66, contacts 31, to the point P- on the resistance 33, but there will still be a portion of the current passing through the coil 226,- as before described, and meeting the circuit last traced, at the point PF onresistance 33. Thev strength of the current passing through the coil istherefore suiicient to maintain switch No.5closed until -switch No. 1 is actuated. Contacts 41 will then be closed against switch arm 40 and the resistance 38 thrown in parallel with the resistance 33 and in series with the remain-v ing portion of the' dynamic brake circuit. Since wirev223 is connected to wire 39 adjacent switch No. 1, the current which has heretofore passed over wire 223 and. coil 226 vswitch No. 13 to resume its normal position,

the effect of which will be to open the short circuit around resistance 14 anda portion of resistance 15, as will be clear fromFig. 5. After switch No. 5 has resumed its normal position then switch No. 4 willv also resume its normal position, which will be clear from the simplified diagram shown in Fig. 8 of the drawings. Upon the closing of contacts 31 of switch No. 2,' that is, upon the breaking of the switches for the third speed of the motor, the high resistance coil 219 is short circuited but the other high resistance winding 233 is still energized until switch No. 5 has resumed its normal position, so that switch arm 60 is again in contact with contacts 59; but when this occurs the portion of the resistance 56 with which the i l circuit of the coil 233 is in parallel, will be short circuited, thus cutting olf the current which asses through the coil so that it has not su cient stren, ?;th to maintain its armature attracted. However, aslong as switch -No. 5 is in its actuated position, or in other y controlling circuit for pilot magnet of switch No. 3--As has been previously described. the high resistance winding 214 of this coil is in parallel with a part of the resistance of the main circuit and current will flow through the same as long as the main kline is being which is wound .to oppose the iux through coil 214, is, upon the switch No. 4 resuming its normal position, connected to the dynamic brake circuit. Since the ux passing supplied. However, coil 52 of. this magnet,

through the coil 52 opposes the iux through coil 214, if the dynamic current is strong the coil 52 will nullify the attractive action of .coil 214 and switch No. 11 will assume its normal position, breaking the circuitv to switch No. 3. If, however, the motor is still receiving a strong line current, as where the load is such that more current is needed to operate the motor, Vthe attractive force of coil 214 will besuliicient to hold the switch No. 11 in its attracted position against the neutralizing laction of coil 52, which insures that the motor will not be stopped'before the car reaches the desired plane, as might otherwise occur. It will be seen, therefore, that switches 5, 4 and 3 may vresume their normal positions only in reverse order to the order 1n which they are actuated.

Upon the. breaking of the control circuits for vthe first speed either u or down, the coils for the up and own switches Will be denergized, the switches resuming their normal pf sition and the motor coming 

